Transcript Security Risks and Precautions

Security Risks
As computer’s have a greater role in our everyday life
opportunities for technology crime have been created. All
networks need to have security measures in place or they could
be remotely accessed by a hacker.
A hacker is a computer enthusiast who spend lots of time and effort trying to gain
unauthorised access to a computer system. If they are malicious they may disrupt
systems by changing, deleting or copying data while others are deliberately intent
on defrauding companies.
Nowadays a great deal of time, effort and money is spent attempting to make computer
networks as secure as possible from unauthorised access.
It is particularly important to make sure wireless networks are secure because wireless data
can be easily intercepted. Both wired and wireless networks should be password protected
and the transferred data encrypted to make sure only authorised people can access the
network.
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Security Risks
Malware (Malicious software) is used to
describe any piece of software which is
malicious or damaging to a computer.
Viruses, worms and Trojan horses are some
examples of malware.
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Security Risks : Viruses
A virus is a malicious piece of code which can
cause damage to a computer system. It is a
computer program that attaches itself to
programs and files on your computer.
For a piece of computer code to be a virus is has to do two things:
1. create copies of itself to create a new file
2. attach itself to a file.
You can tell when your computer has a virus as it starts to do unusual
things. These include data going missing, space being used up on
your hard disk or simply your computer running slowly. If a computer
on a network has a virus, it can easily spread to the other computers
through the network. A virus can even cause a computer to break
down by changing its voltage settings.
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Security Risks : Worms
A worm self replicates (copies itself) like
a virus but it can not attach itself to a file.
For this reason it is not technically a
‘virus’ but it can have the same effect.
They can quickly spread by ‘crawling’
through networks.
The most harmful worms reside in the
computer’s memory only. They don’t
save any code to hard disks or any other
type of backing storage. This means that
when you switch your computer off the
worm is lost.
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Security Risks : Trojans
A Trojan is a program which can attach itself to
a file but cannot self-replicate. It is a program
which looks harmless and tricks you into
running it on your computer. It then carries
out its real task, for example displaying adverts
on the desktop or installing unwanted
toolbars.
The most common thing they do is open a
‘back door’ to give remote access to the
computer. It is named after the Trojan Horse
story from classical history when the Greek
warriors hid inside a huge wooden horse to
gain access to the city of Troy.
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Security Risks
Now attempt Task 4 on page 17 of your booklet.
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Security Risks : Spyware
Spyware is a type of malware which secretly
monitors the user’s computer. These programs
gather information about you from your
computer. This can be personal information or
information about the websites you have
visited.
A keylogger is an example of spyware. The
program detect the keys a user presses on a
keyboard. The ASCII code for each key is
identified and saved in a file which can then be
analysed. It is most commonly used by hackers
to detect usernames, passwords and credit
card numbers.
Online games are especially targeted by
hackers using keylogger technology to detect
usernames and passwords.
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Security Risks : Phishing
Phishing is an attempt to get your personal
information such as your login or bank details
by pretending to be, for example a charity or
claiming that you have won a prize. Phishing
can use key loggers, trojans, spyware and even
ordinary e-mail to steal your personal
information. If you are a victim of phishing you
may receive an email asking you to confirm
your bank account details or a password. The
authors of Phishing e-mails spend a lot time
ensuring that the e-mails look as legitimate as
possible.
Most companies would never ask for this
information in an email so you should not
reply to it.
http://www.youtube.com/watch?v=K8lWLwuiDwk
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Security Risks : Online Fraud
Online fraud is the use of the Internet to commit
crime for financial gain.
There are many types of online fraud:
Bank and cheque fraud
Charity donation fraud
Government agency scams
Holiday fraud
Identity theft (see later)
Loan scams
Online shopping fraud
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Security Risks : Identity Theft
This is when people steal your personal information
such as bank account details. The information could
then be used to:
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shop online
apply for a loan
withdraw money from your account
get a work permit to stay in a country
pretend to be another person to rent a property
and many more…
Keyloggers, trojans, spyware and ordinary email can
be used to steal your identity.
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Security Risks : Denial of Service (DOS)
Denial of Service (DOS) Attacks
This is a particularly nasty type of attack targeted mostly at large corporations
that someone has a grudge against. There are two main forms of Denial Of
Service:
 Attacks that consume network resources like processor time, disk space,
memory, network connections and modems, so that there are none left for
normal users.
 Attacks on a specific network resource, for example attacking and disabling a
server.
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Security Risks : Denial of Service (DOS)
Methods used:
1 Resource starvation
This means using up a network resource (server processor time, network storage) so
that real users can’t access it.
2 Bandwidth consumption
This means flooding the network with useless traffic. An example of this is flooding an
email server until it either crashes or denies email services to legitimate users because
its too busy.
3 Hacking network software
If networking software like firewalls or operating systems are not protected or have
bugs in them, hackers can use these weaknesses to crash servers.
http://www.youtube.com/watch?v=3eLx2LG5pPY
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Security Risks : Denial of Service (DOS)
Methods used:
4 Attacking the routers
Routers are vulnerable to PING (Packet Internet Groper) attacks where bad data is
sent.
5 Domain Name Server (DNS attacks)
This type of attack disrupts network access by causing the server to keep looking for
things that do not exist. This means that correct requests are not dealt with.
Effects of DOS attacks
Whichever method is adopted, the effects are clear: the attack disrupts use of the
network and denies the legitimate users access to the network services and resources,
for example email is not available, data files can’t be accessed or Internet access is
denied.
http://www.youtube.com/watch?v=3eLx2LG5pPY
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Security Risks
Now attempt Tasks 5 & 6 on page 22 of your booklet.
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Security Precautions
There are a variety of different ways of protecting computers,
access to computer networks and data on computers.
1 Passwords
The most common way of controlling access to a computer
system or network is to use a system of IDs (user names) and
passwords.
You must be careful to use passwords that are hard to break.
Favourite bands, family names etc are all easy to hack.
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Security Precautions
2 Encryption
Encryption is a means of encoding/scrambling data using encryption
keys. Today very sophisticated encryption keys are used involving
carrying out calculations on the binary data. For an encryption key
to be effective it should take a computer many years to work out
the decryption algorithm.
Simple example of encryption
The following word has been encrypted.
Can you decrypt it?
IFMMP
Encrypting and decrypting files is big business as companies and
governments race to protect their own information and access others.
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Security Precautions
3 Firewall Software
Network managers keep their networks safe and secure by installing
firewall software or firewall hardware. Firewalls help prevent
unauthorised access to computers by stopping hackers accessing
private information stored on computers.
Firewall software or hardware can allow us to block the IP address
of a computer we think might be trying to access our computers
illegally.
Anyone who gains unauthorised access to a computer system is
breaking the Computer Misuse Act.
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Security Precautions
4 Biometric Systems
Biometrics is the science and technology of measuring and analysing biological
data.
In Computing Science, biometrics refers to technologies that measure and
analyse human body characteristics, such as DNA, fingerprints, eye retinas and
irises, voice patterns, facial patterns and hand measurements, for authentication
purposes. Biometrics systems can be used to limit access to computer rooms or
computer systems.
Retina & iris recognition
The person’s unique retina and/or iris are recognized using a
biometric sensor. If the unique pattern in their eye is recognised
the person is allowed access to the computer room.
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Security Precautions
4 Biometric Systems (continued)
Fingerprint recognition
Every person’s fingerprint patterns are different.
By reading the fingerprint with a scanner that reads key points
in the pattern the user may be recognised.
Face recognition
Face recognition uses biometric sensor to map landmarks
(nodal points) on the users face. Examples of landmarks are:
Distance between the eyes
Width of the nose
Depth of the eye sockets
The shape of the cheekbones
The length of the jaw line
The advantage of using biometric systems for security is that it is much harder to forge a
fingerprint or retina pattern than it is to hack to system that relies on passwords or PIN
numbers. Additionally, there is no need for the user to remember passwords.
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Security Precautions
5 Anti-Virus Software
Anti-virus software is used to prevent computer viruses from
damaging computer systems. It locates the virus program code and
then quarantines (locks it away from the rest of the system) and
deletes it.
There are many anti-virus programs available but they all operate in
similar ways. Virus scans are performed as often as the user
requires (hourly, daily weekly) by changing settings in the program.
At regular intervals, the software will download ‘definitions’ of new
viruses, allowing the software to keep up-to-date with the latest
threats.
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Security Precautions
6 Security Suites
Nowadays companies selling security software offer more than just anti-virus
software. The following packages may come bundled as a Security Suite:
 Antivirus protection
 Firewall
 Spamkiller
 Spyware protection
 E-mail protection
Note that security software is often sold as a time-limited licence, usually for
one year. This forces customers into an annual payment if they wish to keep
their computer systems protected.
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Security Risks
Now attempt Task 7 on page 24 of your booklet.
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